The jit compiler backend implementation for the s390x architecutre.
The backend manages 64-bit values in the literal pool of the assembly instead of loading them as immediates.
It includes a simplification for the operation ‘zero_array’. Start and length parameters are bytes instead of size.

Improve the tracing speed in the frontend as well as heapcache by using a more compact representation
of traces

Wrap more POSIX functions in rpython.rlib.rposix.

A local clean-up in the JIT front-end.

Remove the forced minor collection that occurs when rewriting the
assembler at the start of the JIT backend. This is done by emitting
the ConstPtrs in a separate table, and loading from the table. It
gives improved warm-up time and memory usage, and also removes
annoying special-purpose code for pinned pointers.

Remove old uneeded numpy headers, what is left is only for testing. Also
generate pypy_numpy.h which exposes functions to directly use micronumpy
ndarray and ufuncs

Reuse rposix definition of TIMESPEC in rposix_stat, add wrapper for fstatat().
This updates the underlying rpython functions with the ones needed for the
py3k branch